A223484 Rolling icosahedron face footprints: number of 6 X n 0..19 arrays starting with 0 where 0..19 label faces of an icosahedron and every array movement to a horizontal or antidiagonal neighbor moves across an icosahedral edge.

3200000, 177147, 6834375, 263671875, 12755926575, 622332801675, 31621425535575, 1608341612382675, 82456836767805375, 4227484231555443675, 217015136003889260775, 11140133589863412595875, 571949483621302897613775

Offset

1,1

Comments

Row 6 of A223480.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 65*a(n-1) -392*a(n-2) -21060*a(n-3) +271696*a(n-4) -61920*a(n-5) -12301824*a(n-6) +41001664*a(n-7) +141738752*a(n-8) -796132352*a(n-9) -244873216*a(n-10) +5515101184*a(n-11) -3510669312*a(n-12) -15177555968*a(n-13) +15458697216*a(n-14) +13446168576*a(n-15) -14442954752*a(n-16) -4507631616*a(n-17) +3989831680*a(n-18) +252706816*a(n-19) -251658240*a(n-20) for n>25.

Example

Some solutions for n=3
..0..5..0....0..5..0....0..5..0....0..5..0....0..5..0....0..5..0....0..5..0
..0..1..0....0..1..0....0..1..0....0..1..4....0..1..4....0..1..0....0..1..4
..0..1..4....6..1..0....6..1..4....4.17..4....4..1..4....4..1..6....0..1..4
..4..1..0....0..5..9....4..1..0...10.17.10....4.17.18....0..1..4....0..1..0
..0..1..4....9..5..0....4..1..6....4.17.10...18.16.18....4.17.10....0..1..4
..0..1..4....0..2..3....6..7..5....4.17.10...18.17..4...10.12.10....4..3.16
Face neighbors:
0 -> 1 2 5
1 -> 0 4 6
2 -> 0 3 8
3 -> 2 4 16
4 -> 3 1 17
5 -> 0 7 9
6 -> 1 7 10
7 -> 6 5 11
8 -> 2 9 13
9 -> 8 5 14
10 -> 6 12 17
11 -> 7 12 14
12 -> 11 10 19
13 -> 8 15 16
14 -> 9 11 15
15 -> 14 13 19
16 -> 3 13 18
17 -> 4 10 18
18 -> 16 17 19
19 -> 15 18 12

Crossrefs

Cf. A223480.

Sequence in context: A234689 A232619 A223287 * A029820 A146976 A251529

Adjacent sequences: A223481 A223482 A223483 * A223485 A223486 A223487

Keyword

nonn

Author

R. H. Hardin Mar 20 2013

Status

approved